libjava/classpath/java/text/Format.java

   1 /* Format.java -- Abstract superclass for formatting/parsing strings.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2003, 2005  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.text;
  40
  41 import gnu.java.text.FormatCharacterIterator;
  42
  43 import java.io.Serializable;
  44
  45 /**
  46  * This class is the abstract superclass of classes that format and parse
  47  * data to/from <code>Strings</code>.  It is guaranteed that any
  48  * <code>String</code> produced by a concrete subclass of <code>Format</code>
  49  * will be parseable by that same subclass.
  50  * <p>
  51  * In addition to implementing the abstract methods in this class, subclasses
  52  * should provide static factory methods of the form
  53  * <code>getInstance()</code> and <code>getInstance(Locale)</code> if the
  54  * subclass loads different formatting/parsing schemes based on locale.
  55  * These subclasses should also implement a static method called
  56  * <code>getAvailableLocales()</code> which returns an array of
  57  * available locales in the current runtime environment.
  58  *
  59  * @author Aaron M. Renn (arenn@urbanophile.com)
  60  * @author Per Bothner (bothner@cygnus.com)
  61  */
  62 public abstract class Format implements Serializable, Cloneable
  63 {
  64   /**
  65    * For compatability with Sun's JDK 1.4.2 rev. 5
  66    */
  67   static final long serialVersionUID = -299282585814624189L;
  68
  69   public static class Field extends AttributedCharacterIterator.Attribute
  70   {
  71     static final long serialVersionUID = 276966692217360283L;
  72
  73     protected Field(String name)
  74     {
  75       super(name);
  76     }
  77   }
  78
  79   /**
  80    * This method initializes a new instance of <code>Format</code>.
  81    * It performs no actions, but acts as a default constructor for
  82    * subclasses.
  83    */
  84   protected Format ()
  85   {
  86   }
  87
  88   /**
  89    * This method formats an <code>Object</code> into a <code>String</code>.
  90    *
  91    * @param obj The <code>Object</code> to format.
  92    *
  93    * @return The formatted <code>String</code>.
  94    *
  95    * @exception IllegalArgumentException If the <code>Object</code>
  96    * cannot be formatted.
  97    */
  98   public final String format(Object obj) throws IllegalArgumentException
  99   {
 100     StringBuffer sb = new StringBuffer ();
 101     format (obj, sb, new FieldPosition (0));
 102     return sb.toString ();
 103   }
 104
 105   /**
 106    * This method formats an <code>Object</code> into a <code>String</code> and
 107    * appends the <code>String</code> to a <code>StringBuffer</code>.
 108    *
 109    * @param obj The <code>Object</code> to format.
 110    * @param sb The <code>StringBuffer</code> to append to.
 111    * @param pos The desired <code>FieldPosition</code>, which is also
 112    *            updated by this call.
 113    *
 114    * @return The updated <code>StringBuffer</code>.
 115    *
 116    * @exception IllegalArgumentException If the <code>Object</code>
 117    * cannot be formatted.
 118    */
 119   public abstract StringBuffer format (Object obj, StringBuffer sb,
 120                                        FieldPosition pos)
 121     throws IllegalArgumentException;
 122
 123   /**
 124    * This method parses a <code>String</code> and converts the parsed
 125    * contents into an <code>Object</code>.
 126    *
 127    * @param str The <code>String</code> to parse.
 128    *
 129    * @return The resulting <code>Object</code>.
 130    *
 131    * @exception ParseException If the <code>String</code> cannot be parsed.
 132    */
 133   public Object parseObject (String str) throws ParseException
 134   {
 135     ParsePosition pos = new ParsePosition(0);
 136     Object result = parseObject (str, pos);
 137     if (result == null)
 138       {
 139         int index = pos.getErrorIndex();
 140         if (index < 0)
 141           index = pos.getIndex();
 142         throw new ParseException("parseObject failed", index);
 143       }
 144     return result;
 145   }
 146
 147   /**
 148    * This method parses a <code>String</code> and converts the parsed
 149    * contents into an <code>Object</code>.
 150    *
 151    * @param str The <code>String</code> to parse.
 152    * @param pos The starting parse index on input, the ending parse
 153    *            index on output.
 154    *
 155    * @return The parsed <code>Object</code>, or <code>null</code> in
 156    *         case of error.
 157    */
 158   public abstract Object parseObject (String str, ParsePosition pos);
 159
 160   public AttributedCharacterIterator formatToCharacterIterator(Object obj)
 161   {
 162     return new FormatCharacterIterator(format(obj), null, null);
 163   }
 164
 165   /**
 166    * Creates a copy of this object.
 167    *
 168    * @return The copied <code>Object</code>.
 169    */
 170   public Object clone ()
 171   {
 172     try
 173       {
 174         return super.clone ();
 175       }
 176     catch (CloneNotSupportedException e)
 177       {
 178         return null;
 179       }
 180   }
 181 }